Steroid Regulation of Ion Channels

离子通道的类固醇调节

• 批准号: 6865492
• 负责人: LESLIE P HENDERSON
• 金额: $ 23.85万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6865492
• 关键词: Steroid; Regulation; Ion; Channels

EXCEED THE SPACE PROVIDED. Anabolic-androgenic steroids (AAS) are synthetic derivatives of testosterone developed for hypogonadism and treatment of wasting disorders. While still invaluable therapeutic tools, illicit use of suprapharmacological doses of AAS has overshadowed their clinical use, not only with respect to elite athletes, but also a growing number of "ordinary citizens", and most disturbingly, an appreciable number of adolescents. Chronic AAS use in both human subjects and animal models is associated with marked behavioral changes; the most notable of which are in sexual/reproductive behaviors, aggression and anxiety. Neurotransmission mediated by 7-3minobutyric acid type A (GABAA) receptors in the forebrain plays a crucial role in the expression of all of these behaviors. Interestingly, positive mood symptoms, including euphoria, hypomania and decreased anxiety are also reported, either immediately after exposure or early in the course of AAS use. These effects are reminiscent of the actions of benzodiazepines, ethanol and neurosteroids, and suggest that some of the early positive behavioral manifestations in AAS use may also arise from allosteric modulation of forebrain GABAergic transmission. We have previously shown that chronic AAS treatment alters GABAA receptor expression and function in the basal forebrain in an age- and sex-specific manner. We have also shown that acute AAS administration rapidly alters GABAA receptor function via allosteric modulation and that this modulation depends upon subunit composition. In the current proposal, we will take advantage of a transgenic mouse strain to determine the role of the E subunit in how the AAS alter GABAergic transmission in gonadotropin releasing hormone (GnRH) neurons that control the hypothalamic-pituitary-gonadal axis and are therefore the key regulators of pubertal onset and reproductive maturation. We will take advantage of a specific GABAA receptor subunit knockout strain of mice to determine the role of the a subunits in regulating AAS modulation of neural circuits important for the expression of anxiety. Finally, we will assess how posttranslational modifications of the GABAA receptor regulate allosteric modulation by the AAS and if these changes vary with the age,sex and hormonal state. To these ends we will use whole cell patch clamp recording from acutely isolated brain slices coupled with single cell real time PCR; ultrafast perfusion to recombinant receptors in heterologous cells, and behavioral assessment (ethological elevated plus maze) for anxiolytic effects of the AAS. While the behavioral actions of the AAS are well documented, the underlying neural substrates for these effects are not well known. Our data will generate data important for understanding how these steroids alter neuronal function to produce effects on reproductive and mental health, and how their effects differ in men vs. women and adults vs. children who abuse them. PERFORMANCE SITE ========================================Section End===========================================

超出所提供的空间。合成代谢雄激素类固醇（AAS）是睾酮的合成衍生物，用于性腺功能减退和治疗消耗障碍。虽然仍然是宝贵的治疗工具，但非法使用超药物剂量的AAS使其临床应用黯然失色，不仅对精英运动员，而且对越来越多的“普通公民”，以及最令人不安的是，相当数量的青少年。在人类受试者和动物模型中，长期使用AAS与显著的行为改变有关；其中最显著的是性/生殖行为、攻击性和焦虑。前脑7-3氨基丁酸A型（GABAA）受体介导的神经传递在所有这些行为的表达中起着至关重要的作用。有趣的是，积极情绪症状，包括欣快感，轻躁狂和减少焦虑也被报道，要么在暴露后立即或在AAS使用过程的早期。这些影响让人想起苯二氮卓类药物、乙醇和神经类固醇的作用，并提示使用AAS的一些早期阳性行为表现也可能来自前脑gaba能传递的变构调节。我们之前已经表明，慢性AAS治疗会以年龄和性别特异性的方式改变基底前脑中GABAA受体的表达和功能。我们还表明，急性AAS给药通过变构调节迅速改变GABAA受体功能，这种调节取决于亚基组成。在目前的提案中，我们将利用转基因小鼠品系来确定E亚基在AAS如何改变促性腺激素释放激素（GnRH）神经元中gaba能的传递中的作用，这些神经元控制下丘脑-垂体-性腺轴，因此是青春期开始和生殖成熟的关键调节因子。我们将利用小鼠特异性GABAA受体亚基敲除菌株来确定a亚基在调节AAS对焦虑表达重要的神经回路中的作用。最后，我们将评估GABAA受体的翻译后修饰如何通过AAS调节变构调节，以及这些变化是否随年龄、性别和激素状态而变化。为此，我们将使用全细胞膜片钳记录急性分离的脑切片，并结合单细胞实时PCR；在异源细胞中超快灌注重组受体，并对AAS的抗焦虑作用进行行为评估（行为学升高加迷宫）。虽然AAS的行为行为有很好的记录，但这些影响的潜在神经基质尚不清楚。我们的数据将产生重要的数据，以了解这些类固醇如何改变神经元功能，从而对生殖和心理健康产生影响，以及它们对滥用它们的男性与女性、成人与儿童的影响有何不同。网站性能 ======================================== 节结束 ===========================================